Ulster Unionist leader Mike Nesbitt has led calls for next Saturday's Union flag protest in Belfast city centre to be called off out of respect for a parade to honour two murdered soldiers.

Up to 1,000 people are expected to mark the 25th anniversary of the murders of UDR soldiers James Cummings and Fred Starrett in a 1998 IRA bomb attack on Royal Avenue. First Minister Peter Robinson added his voice to Mr Nesbitt's call – but protest supporters have refused to listen.

"I view this as a cynical attempt to use the UDR parade and the protest to undermine each other and create divisions within our community," said Jamie Bryson of the Ulster Protestant Voice.

Saturday flag protests, which block the roads and hit trade, have been a weekly feature of Belfast life since early December. That was when the council voted to reduce the number of days on which the Union flag would be flown above City Hall.

Numbers have been dwindling in recent weeks and there had been hopes that the UDR parade would provide protesters with a face-saving way out.

"Given the cost of the flags protests, it would be regrettable if those involved did not take the opportunity to step back to allow the media to highlight how republicans once stopped at nothing to pursue their economic war against Northern Ireland, irrespective of the cost in terms of human lives or impact on the economy," Mr Nesbitt said. His call was echoed by DUP leader Mr Robinson, who said protesters may see "the real benefit of putting the focus on the death of two soldiers at the hands of the IRA".

Meanwhile, the board of Crusaders FC urged loyalists not to protest at their north Belfast Seaview ground again after loyalist protesters clashed with police at the weekend. The board apologised after trouble forced the Cliftonville match to be called off.

"Politics play no part in sport," the club said in a statement. "We are requesting that our members, supporters, local residents, community groups, schools, churches, politicians, sporting bodies, and all other interested parties use all their influence to put an end to flag protests in the environs of our stadium."